rakuten-mcp

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the search functionality but doesn't describe what the tool returns (e.g., hotel listings with details), error conditions, rate limits, or authentication requirements. For a search tool with no annotations, this leaves significant behavioral gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with zero waste. The first sentence states the purpose, and the second provides crucial usage guidance. Every word earns its place, and the information is front-loaded effectively.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no annotations and no output schema, the description adequately covers purpose and usage guidelines but lacks details on return values, error handling, or behavioral constraints. For a search tool with 3 parameters and no structured output documentation, this is a minimum viable description with clear gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already fully documents all three parameters (keyword, hits, page). The description doesn't add any parameter-specific details beyond what's in the schema, such as keyword formatting examples or pagination behavior. Baseline 3 is appropriate when the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the specific action ('Search for hotels') on a specific resource ('Rakuten Travel') using a specific method ('by keyword'). It explicitly distinguishes this tool from its sibling 'search_travel_vacancy' by specifying what this tool does versus what the alternative handles.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit guidance on when to use this tool ('Search for hotels... by keyword') versus when to use an alternative ('For availability/date/price search, use search_travel_vacancy instead'). This gives clear context for tool selection among siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.